A recent remark by Taro Aso, vice president of the Liberal Democratic Party, calling senior members of the party's junior coalition partner, Komeito, a "cancer" has upset lawmakers of the ruling bloc.

According to media reports and other sources, Aso said at a meeting in the city of Fukuoka on Sunday that Komeito leader Natsuo Yamaguchi, other Komeito executives and the party's main supporter, the lay Buddhist group Soka Gakkai, were a "cancer" that impeded efforts over the revision of Japan's three key security documents last December.

Komeito was opposed to the policy of acquiring counterstrike capabilities, newly included in the documents, saying it would run counter to Japan's exclusively defense-oriented policy, Aso said.

"They came around to tolerating it after we kept on saying that Japan would become a battlefield like Ukraine right now," the veteran politician added.

The remark came just after the two parties revived earlier this month cooperation in Tokyo for the next general election.

"The relationship of trust that we have built up may collapse," a Komeito member said angrily.

"Our supporters will lose the will to back LDP candidates," another Komeito member said. "It is the LDP that will be in trouble."

Yamaguchi avoided commenting on Aso's remark at a news conference Tuesday, saying that he did not know their context.